Pump structure

ABSTRACT

A pump apparatus may include an inner rotor, a driving shaft, a curved surface formed at an inner circumference portion of the inner rotor into which the driving shaft may be inserted, the curved surface being formed by a plurality of curves along a rotation direction of the driving shaft, and a pressing body slidably engaged in the driving shaft and elastically pressed in a radial direction of the driving shaft by the plurality of curves.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority to Korean Patent Application No.10-2013-0157909, filed on Dec. 18, 2013, the entire contents of which isincorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION

1 Field of the Invention

The present invention relates to a pump structure, and moreparticularly, to a fuel pump structure of pumping fuel of a vehicle.

2. Description of Related Art

FIG. 1 shows a fuel pump structure according to the related art, wherethe fuel pump structure is configured so that fuel is pumped byrelatively and rotatably installing an inner rotor 502 and an outerrotor 504 in a housing 500 and rotating the inner rotor 502 by a drivingshaft 506.

Here, the driving shaft 506 is connected to the inner rotor 502 in astate in which it may transfer rotational force to the inner rotor 502and a detailed structure thereof may be shown as in FIG. 2.

That is, the driving shaft 506 and the inner rotor 502 have a keyway 508formed therebetween so as to constrain each other in a rotationdirection and a key 510 is inserted into the keyway 508, such that therotational force from the driving shaft 506 may be smoothly transferredto the inner rotor 502.

However, when a gear stick or the like occurs in the fuel pump in thestate in which the driving shaft 506 and the inner rotor 502 areconstrained to each other by the key 510, if the driving shaft 506 iscontinuously applied with the rotational force from the outside, thedriving shaft 506 may be damaged.

In addition, the fuel pump includes a relief valve configuration toprevent over-pressure from being generated. However, when the reliefvalve is stuck, an oil leak, damage, or the like for a fuel hose or afuel filter may be caused by over-pressure discharge.

The information disclosed in this Background of the Invention section isonly for enhancement of understanding of the general background of theinvention and should not be taken as an acknowledgement or any form ofsuggestion that this information forms the prior art already known to aperson skilled in the art.

BRIEF SUMMARY

Various aspects of the present invention are directed to providing apump structure capable of preventing damage to a driving shaft andpreventing oil leak, damage, or the like of a fuel hose or a fuel filterin a situation in which the damage to the driving shaft is generated bycontinuously applying excessive rotational force to the driving shaftdue to a mechanical stick caused in a fuel pump and a situation in whichthe oil leak, damage, or the like of the fuel hose or the fuel filter isconcerned due to excessive fuel pressure formed in a fuel supplying linedue to failure generated from a relief valve included in the fuel pump.

In an aspect of the present invention, a pump apparatus may include aninner rotor, a driving shaft, a curved surface formed at an innercircumference portion of the inner rotor into which the driving shaft isinserted, the curved surface being formed by a plurality of curves alonga rotation direction of the driving shaft, and a pressing body slidablyengaged in the driving shaft and elastically pressed in a radialdirection of the driving shaft by the plurality of curves.

The curved surface of the inner rotor is formed by repeating bentstraight lines and is formed at an entire portion of the innercircumference portion in the inner rotor.

The curved surface of the inner rotor may include upper and lower ridgesalternatively repeated between the bent straight lines.

The pressing body may include a spherical ball, wherein at least aportion of the spherical ball is slidably positioned in the drivingshaft in a state in which the spherical ball is selectively pressedtoward the curved surface.

The pump apparatus may include a guide groove that is formed in thedriving shaft along the radial direction thereof so that the pressingbody is movable along the radial direction according to a rotation ofthe inner rotor, and an elastic member positioned inside the guidegroove and applying elastic force to the pressing body against the innercircumference portion of the inner rotor.

The elastic member may include a coil spring, the pressing body mayinclude a spherical ball, and a slide guide is placed between theelastic member and the pressing body inside the guide groove andsupported by the elastic member to linearly slide in the guide groove soas to apply the elastic force provided by the elastic member to thepressing body.

The pressing body may include a spherical ball.

The methods and apparatuses of the present invention have other featuresand advantages which will be apparent from or are set forth in moredetail in the accompanying drawings, which are incorporated herein, andthe following Detailed Description, which together serve to explaincertain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a configuration view showing a fuel pump structure accordingto the related art.

FIG. 2 is a detailed view showing a connection structure of an innerrotor and a driving shaft of FIG. 1.

FIG. 3 is a view showing the connection structure of the inner rotor andthe driving shaft as a pump structure according to an exemplaryembodiment of the present invention.

FIG. 4, which is a view describing an operation of the presentinvention, is a view describing a case in which power of the drivingshaft is not transferred to the inner rotor when a pump stick and anexcessive pumping pressure are generated.

It should be understood that the appended drawings are not necessarilyto scale, presenting a somewhat simplified representation of variousfeatures illustrative of the basic principles of the invention. Thespecific design features of the present invention as disclosed herein,including, for example, specific dimensions, orientations, locations,and shapes will be determined in part by the particular intendedapplication and use environment.

In the figures, reference numbers refer to the same or equivalent partsof the present invention throughout the several figures of the drawing.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments of thepresent invention(s), examples of which are illustrated in theaccompanying drawings and described below. While the invention(s) willbe described in conjunction with exemplary embodiments, it will beunderstood that the present description is not intended to limit theinvention(s) to those exemplary embodiments. On the contrary, theinvention(s) is/are intended to cover not only the exemplaryembodiments, but also various alternatives, modifications, equivalentsand other embodiments, which may be included within the spirit and scopeof the invention as defined by the appended claims.

Referring to FIG. 3, a pump structure according to an exemplaryembodiment of the present invention may be configured to include acurved surface 5 formed at an inner circumference portion of an innerrotor 3 into which a driving shaft 1 is inserted, the curved surface 5is formed by a plurality of curves along a rotation direction of thedriving shaft 1, and a pressing body 7 elastically pressed in a radialdirection from the driving shaft 1 toward the curved surface 5.

That is, the driving shaft 1 and the inner rotor 3 are coupled so thatwhen a predetermined level or more of relative torque is applied betweenthe driving shaft 1 and the inner rotor 3, the pressing body 7 movesalong the curved surface 5 to thereby relatively rotate the drivingshaft 1 and the inner rotor 3, unlike a state according to the relatedart in which the relative rotation of the driving shaft 1 and the innerrotor 3 is completely impossible. Thereby, excessive rotational force isnot applied to the driving shaft 1, thereby making it possible toprevent damage to the driving shaft 1. In addition, even in the case inwhich a relief valve fails, when excessive pumping pressure isgenerated, the driving shaft 1 and the inner rotor 3 relatively rotate,thereby making it possible to prevent oil leak and damage to a fuel hoseor a fuel pump.

According to the present embodiment, the curved surface 5 of the innerrotor 3 is formed by repeating bent straight lines and has a structureformed at the entire circumference of the inner circumference portion ofthe inner rotor 3.

Therefore, as shown in FIG. 4, the pressing body 7 is allowed todifficultly cross upper and lower ridges 10 and 20 of the curved surface5, such that the relative rotation of the driving shaft 1 and the innerrotor 3 is sufficiently limited in a normal operation state and may beperformed only in an inevitable situation, thereby making it possible tosecure more stable operation of the fuel pump.

In an exemplary embodiment of the present invention, the upper and lowerridges 10 and 20 of the curved surface 5 are alternatively formed alongthe inner circumference of the inner rotor 3.

The pressing body 7 is configured of a spherical ball and the ball isformed so that at least a portion thereof is positioned in the drivingshaft 1 in a state in which it is maximally pressed toward the curvedsurface 5.

Therefore, when the driving shaft 1 and the inner rotor 3 are relativelyrotated, the pressing body 7 may perform a cloud motion on the curvedsurface 5 so as not generate excessive abrasion or noise between thepressing body 7 and the inner rotor 3 and the rotational force of thedriving shaft 1 may be stably transferred to the inner rotor 3 throughthe pressing body 7.

A guide groove 9 is formed in the driving shaft 1 along the radialdirection so that the pressing body 7 may be moved along the radialdirection and includes an elastic member 11 for applying elastic forceto the pressing body 7.

According to the present embodiment, there is provided a structure thatthe elastic member 11 is configured of a coil spring, the pressing body7 is configured of the spherical ball as described above, and a slideguide 13 linearly sliding in the guide groove 9 and capable of applyingelastic force provided by the elastic member 11 to the pressing body 7is included between the elastic member 11 and the pressing body 7.

Therefore, the slide guide 13 allows a degree of freedom of a shape anda size of the elastic member 11 and the elastic force provided by theelastic member 11 may be stably transferred to the pressing body 7, suchthat power of the driving shaft 1 is stably transferred to the innerrotor 3 in the normal situation and the relative rotation of the drivingshaft 1 and the inner rotor 3 may be certainly allowed in an abnormalsituation such as stick in the pump, the failure of the relief valve, orthe like, thereby making it possible to secure durability of the drivingshaft 1 and other parts.

According to the exemplary embodiment of the present invention, damageto a driving shaft may be prevented and the oil leak, the damage, or thelike of the fuel hose or the fuel filter may be prevented in a situationin which damage to the driving shaft is generated by continuouslyapplying excessive rotational force to the driving shaft due tomechanical stick caused in the fuel pump and a situation in which theoil leak, damage, or the like of the fuel hose or the fuel filter isconcerned due to excessive fuel pressure formed in a fuel supplying linedue to failure generated from the relief valve included in the fuelpump.

For convenience in explanation and accurate definition in the appendedclaims, the terms “upper”, “lower”, “inner” and “outer” are used todescribe features of the exemplary embodiments with reference to thepositions of such features as displayed in the figures.

The foregoing descriptions of specific exemplary embodiments of thepresent invention have been presented for purposes of illustration anddescription. They are not intended to be exhaustive or to limit theinvention to the precise forms disclosed, and obviously manymodifications and variations are possible in light of the aboveteachings. The exemplary embodiments were chosen and described in orderto explain certain principles of the invention and their practicalapplication, to thereby enable others skilled in the art to make andutilize various exemplary embodiments of the present invention, as wellas various alternatives and modifications thereof. It is intended thatthe scope of the invention be defined by the Claims appended hereto andtheir equivalents.

What is claimed is:
 1. A pump apparatus, comprising: an inner rotor; adriving shaft; a curved surface formed at an inner circumference portionof the inner rotor into which the driving shaft is inserted, the curvedsurface being formed by a plurality of curves along a rotation directionof the driving shaft; and a pressing body slidably engaged in thedriving shaft and elastically pressed in a radial direction of thedriving shaft by the plurality of curves.
 2. The pump apparatus of claim1, wherein the curved surface of the inner rotor is formed by repeatingbent straight lines and is formed at an entire portion of the innercircumference portion in the inner rotor.
 3. The pump apparatus of claim2, wherein the curved surface of the inner rotor includes upper andlower ridges alternatively repeated between the bent straight lines. 4.The pump apparatus of claim 1, wherein the pressing body includes aspherical ball, and wherein at least a portion of the spherical ball isslidably positioned in the driving shaft in a state in which thespherical ball is selectively pressed toward the curved surface.
 5. Thepump apparatus of claim 1, further including: a guide groove that isformed in the driving shaft along the radial direction thereof so thatthe pressing body is movable along the radial direction according to arotation of the inner rotor; and an elastic member positioned inside theguide groove and applying elastic force to the pressing body against theinner circumference portion of the inner rotor.
 6. The pump apparatus ofclaim 5, wherein the elastic member includes a coil spring, wherein thepressing body includes a spherical ball, and wherein a slide guide isplaced between the elastic member and the pressing body inside the guidegroove and supported by the elastic member to linearly slide in theguide groove so as to apply the elastic force provided by the elasticmember to the pressing body.
 7. The pump apparatus of claim 6, whereinthe pressing body includes a spherical ball.